1. Field of the Invention
The present invention relates to a locking apparatus for a sliding cover of a camera. The present invention also relates to a sliding cover apparatus of a camera.
2. Description of the Related Art
In a camera in which the front portion of a photographing lens can open and close via a sliding cover, when the sliding cover is opened, a main switch is turned ON and the photographing lens is advanced from a retracted position to an operational position. In such a camera, a safety device is provided to prevent the closure of the sliding cover when the photographing lens is advanced to the operational position in association with the movement of the photographing lens barrel to thereby prevent an interference of the sliding cover with the photographing lens. In the sliding movement locking apparatus, it is preferable that the safety device operates in association with the movement of the lens barrel to prevent the closure of the sliding cover when the photographing lens is in the operational position. When the photographing lens is moved from the operational position to the retracted position, and if the locking-restraint on the sliding cover is discontinued at the same time as the commencement of the retraction operation of the photographing lens barrel into the camera body, the sliding cover may try to close before the photographing lens is completely retracted, thus resulting in the sliding cover interfering with the photographing lens.
Moreover, in the sliding movement locking apparatus of the type mentioned above, if the sliding cover is forcedly or suddenly moved from the open position to the closed position, the sliding cover engages with the sliding movement locking member, so that it is impossible to cancel the locking-restraint on the sliding cover via the safety device in spite of the retraction of the lens barrel. Consequently, the sliding movement locking safety device or the lens barrel driving system can possibly be damaged due to the excessive force exerted thereon.
It is necessary to stop the sliding cover at the open position or the closed position and to apply a certain amount of friction to the sliding cover during the sliding movement. To this end, the camera body or the sliding cover is provided with a `click spring` and the sliding cover or the camera body is provided with a `click hole` in which the click spring is engaged. The click spring must be always brought into spring-contact with the camera body and the sliding cover, i.e., must be located in a position in which the click spring is not visible even in the open position and the closed position of the sliding cover. To this end, in a known camera, the camera body is provided with an overlap portion which always overlaps the sliding cover in the direction of the sliding movement of the sliding cover, so that the click spring is disposed underneath the overlap portion. However, the overlap portion invites an increase in the sliding movement of the sliding cover, contrary to the miniaturization of the camera.
The assignee of the present application has proposed a dual sliding cover system in which an auxiliary sliding cover is disposed on the rear side of the main sliding cover in the open position, wherein when the main sliding cover is moved toward the closed position, the auxiliary sliding cover is moved further in the same direction relative to the main sliding cover (U.S. Ser. No. 08/784,920). In this dual sliding cover system, the displacement of the main sliding cover can be reduced due to the dual sliding cover plate, and hence the size of the camera in the direction of the movement of the main sliding cover can be reduced. In particular, the increase in the size of the auxiliary sliding cover makes it possible to reduce the displacement of the main sliding cover. However, if the auxiliary sliding cover is larger than a predetermined size, the amount of overlap between the main sliding cover and the auxiliary sliding cover is increased when the main and auxiliary sliding covers are retracted. Consequently, there is a possibility that the overlap portion cannot be provided in the front portion of the camera.